This undated electron microscope image made available by the National Institute of Allergy and Infectious Diseases - Rocky Mountain Laboratories shows a novel coronavirus particle, also known as the MERS virus.

"The death rate of 30 percent of MERS cases is certainly tragic, and the virus is easily transferable among people," Palisano said. "However, even though we need to be worried, I'm not sure it's as dangerous as people think, because we may be able to control it."

Symptoms of MERS

It's also not a superbug. Superbugs are bacteria-based organisms, such as the similarly named MRSA, which have become resistant to the antibiotics used to treat patients.

But one thing MERS is—it's new. It was first reported in Saudi Arabia in 2012. In fact it takes its name from ts region of origin, the Middle East. That's also where the majority of cases have been documented. So far, every reported case of MERS worldwide has been linked to countries in the Arabian Peninsula.

The CDC says it doesn't know exactly where the virus originated, but the likely source is an animal species—specifically, camels.

People affected by the MERS virus develop a severe acute respiratory illness, with symptoms including fever, cough, and shortness of breath. The virus has a current fatality rate of 30 percent, according to the CDC. What medical professionals do is react to the symptoms to control the virus.

The real trouble with MERS may be how easily it spreads. The virus can go from person to person who are in close contact with each other, and that includes transmission from infected patients to health-care workers in hospitals.

The two MERS patients in the U.S. are health care providers who were working in Saudi Arabia.

Experts do not yet know precisely how the virus is spread—whether it's by coughing, or sneezing or simply touching someone.

"We just don't know enough yet on how it's being passed from person to person," said CDC spokesman Jason McDonald in a phone call with CNBC.

However, the CDC advises people to help protect themselves from respiratory illnesses by washing their hands often, avoiding close contact with people who are sick, avoiding touching their own eyes, nose or mouth with unwashed hands, and disinfecting frequently-touched surfaces.

Lesson from SARS

While there is concern that the virus is spreading globally, the CDC does not recommend that Americans change their travel plans—yet. It doesadvise people traveling to the Arabian Peninsula who work in a health care setting to follow CDC's recommendations for infection control.

"It's definitely more of a risk for health care workers who can have contact with people with the virus, " said CDC's McDonald. "And since we don't know how it's spread, they need to take serious precautions."

Public health officials are working with airlines to identify and notify U.S. travelers who may have been in close contact with the Florida patient on any of the several flights that individual took in order to reach the U.S.